Dodge Ram Truck 1500-2500-3500. Manual — part 921
P0579-SPEED CONTROL SWITCH 1 PERFORMANCE (5.7L) (CONTINUED)
For the Engine circuit diagram (Refer to 9 - ENGINE - SCHEMATICS AND DIAGRAMS).
For a complete wiring diagram Refer to Section 8W.
•
When Monitored:
With the ignition key on.
•
Set Condition:
Cruise switch voltage output is not out of range but it does not equal any of the values for any of the button
positions.
Possible Causes
(V37) S/C SWITCH NO.1 SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
(V37) S/C SWITCH NO.1 SIGNAL CIRCUIT OPEN
(V937) SWITCH RETURN CIRCUIT OPEN
(V37) S/C SWITCH NO.1 SIGNAL CIRCUIT SHORTED TO GROUND
(V37) S/C SWITCH NO.1 SIGNAL CIRCUIT SHORTED TO THE (V937) SWITCH RETURN CIRCUIT
CLOCKSPRING
SPEED CONTROL SWITCH
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.
SPEED CONTROL SWITCH STATUS
Start the engine.
With a scan tool, monitor each which function for the Speed Control Switches.
Notice the voltage reading when no buttons are pressed.
Press and release each Speed Control Button.
- Resume/Accel
- Cancel
- Decel (Coast)
- On/Off
- Set
Does each switch function change status when pressing and then depressing each switch?
Yes
>> Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
>> Go To 2
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ENGINE - ELECTRICAL DIAGNOSTICS - 3.7L/4.7L/5.7L
DR/DH
P0579-SPEED CONTROL SWITCH 1 PERFORMANCE (5.7L) (CONTINUED)
2.
SPEED CONTROL SWITCH
Turn the ignition off.
Remove and disconnect the Speed Control Switches from the steering wheel per Service Information.
Measure the resistance across each Speed Control Switch.
Monitor the ohmmeter while pressing each function button on each switch.
The following resistance specs are taken between terminals (V37) S/C Switch No.1 Signal and (V937) S/C Switch
Return circuits of the Switch when holding the switch button in the following position
Not pressing any switch - 20.5 kohms
On/Off - 0.47 kohms
Set - 5.49 kohms
Coast - 2.94 kohms
Cancel - 1.24 kohms
Resume/Accel - 15.4 kohms
Does the function on the Speed Control Switches have the correct resistance value?
Yes
>> Go To 3
No
>> Replace the Speed Control Switch that had the incorrect resistance value.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
3.
(V37) S/C SWITCH NO.1 SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
Disconnect the C3 PCM harness connector.
Ignition on, engine not running.
Measure the voltage on the (V37) S/C Switch No.1 Signal circuit in the
Speed Control harness connector.
Is the voltage above 5.0 volts?
Yes
>> Repair the short to battery voltage in the (V37) S/C Switch
No.1 Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer
to 9 - ENGINE - STANDARD PROCEDURE)
No
>> Go To 4
DR/DH
ENGINE - ELECTRICAL DIAGNOSTICS - 3.7L/4.7L/5.7L
9 - 607
P0579-SPEED CONTROL SWITCH 1 PERFORMANCE (5.7L) (CONTINUED)
4.
CLOCKSPRING
Turn the ignition off.
Disconnect the upper and lower clockspring harness connectors per
Service Information.
Measure the resistance of the (V37) S/C Switch No.1 Signal circuit
between the upper and lower clockspring harness connectors.
Measure the resistance of the (V937) Switch Return circuit between
the upper and lower clockspring harness connectors.
Is the resistance above 5.0 ohms?
Yes
>> Replace the Clockspring per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer
to 9 - ENGINE - STANDARD PROCEDURE)
No
>> Go To 5
NOTE: Connect the Clockspring harness connectors per Service
Information before continuing.
9 - 608
ENGINE - ELECTRICAL DIAGNOSTICS - 3.7L/4.7L/5.7L
DR/DH
P0579-SPEED CONTROL SWITCH 1 PERFORMANCE (5.7L) (CONTINUED)
5.
(V37) S/C SWITCH NO.1 SIGNAL CIRCUIT OPEN
NOTE: The measurement must be taken from both Speed Control
Switch harness connectors.
CAUTION: Do not probe the PCM harness connectors. Probing
the PCM harness connectors will damage the PCM terminals
resulting in poor terminal to pin connection. Install Miller Special
Tool #8815 to perform diagnosis.
Measure the resistance of the (V37) S/C Switch No.1 Signal circuit
from the Speed Control harness connector to the appropriate terminal
of special tool #8815.
Is the resistance below 5.0 ohms for both measurements?
Yes
>> Go To 6
No
>> Repair the open in the (V37) S/C Switch No.1 Signal cir-
cuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer
to 9 - ENGINE - STANDARD PROCEDURE)
6.
(V937) SWITCH RETURN CIRCUIT OPEN
NOTE: The measurement must be taken from both Speed Control
Switch harness connectors.
Measure the resistance of the (V937) Switch Return circuit from the
Speed Control harness connector to the appropriate terminal of special
tool #8815.
Is the resistance below 5.0 ohms for both measurements?
Yes
>> Go To 7
No
>> Repair the open in the (V937) Switch Return circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer
to 9 - ENGINE - STANDARD PROCEDURE)
DR/DH
ENGINE - ELECTRICAL DIAGNOSTICS - 3.7L/4.7L/5.7L
9 - 609
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